A coating is a covering that is applied to the surface of an object, usually referred to as the substrate. The purpose of applying the coating may be decorative, functional, or both. Practically every manufactured product requires a coating, often for protective purposes. A major use of coatings is to prevent or counteract the effects of corrosion.
Corrosion is a naturally occurring process that causes significant changes to the physical structure of a material, usually a metal. These changes can be caused by a chemical reaction when metals are exposed to water, acids, or gases. Corrosion weakens the physical structure of the material and can eventually lead to failure of the affected component. By the time corrosion is visible, the damage can be very costly to repair. National Association of Corrosion Engineers (NACE) estimates that the direct costs for preventing, mitigating, and repairing corrosion in the United States are $276 billion annually, and indirect costs such as lost productivity, litigation, and environmental mitigation may push the total corrosion bill to more than $550 billion (Lalgudi et al., “The Science of Corrosion-Busting Smart Coatings” Paint & Coatings Industry, Mar. 1, 2016).
Generally, various particles can be introduced into coatings. However, commercial coatings include only one reactive particle, or multiple unreactive particles, because of processing limitations. There are no known methods to keep reactive species from interacting during the synthesis. Many coatings are synthesized in a single reaction vessel with sequential additions of the various components. Even if the resulting coating displays a desired phase-separated morphology, the components themselves are in contact prior to phase separation. This common procedure does not allow for two different reactive particles to be segregated into a certain phase.
There is a need for a new capability to fabricate multifunctional coatings with reactive particles that cannot normally be mixed or associated with one another. In view of the shortcomings in the art, improved coating materials and systems, and compositions suitable for these systems, are needed, especially to maintain the mechanical integrity of the coating for corrosion resistance and other applications. In particular, what is desired commercially is an entirely new platform, enabling the fabrication of coatings and materials with multiple functional additives, in an industrially scalable process.